1 // Copyright (c) 2018 The Khronos Group Inc. 2 // Copyright (c) 2018 Valve Corporation 3 // Copyright (c) 2018 LunarG Inc. 4 // 5 // Licensed under the Apache License, Version 2.0 (the "License"); 6 // you may not use this file except in compliance with the License. 7 // You may obtain a copy of the License at 8 // 9 // http://www.apache.org/licenses/LICENSE-2.0 10 // 11 // Unless required by applicable law or agreed to in writing, software 12 // distributed under the License is distributed on an "AS IS" BASIS, 13 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 // See the License for the specific language governing permissions and 15 // limitations under the License. 16 17 #ifndef SOURCE_OPT_DEAD_INSERT_ELIM_PASS_H_ 18 #define SOURCE_OPT_DEAD_INSERT_ELIM_PASS_H_ 19 20 #include <algorithm> 21 #include <map> 22 #include <unordered_map> 23 #include <unordered_set> 24 #include <utility> 25 #include <vector> 26 27 #include "source/opt/basic_block.h" 28 #include "source/opt/def_use_manager.h" 29 #include "source/opt/ir_context.h" 30 #include "source/opt/mem_pass.h" 31 #include "source/opt/module.h" 32 33 namespace spvtools { 34 namespace opt { 35 36 // See optimizer.hpp for documentation. 37 class DeadInsertElimPass : public MemPass { 38 public: 39 DeadInsertElimPass() = default; 40 name()41 const char* name() const override { return "eliminate-dead-inserts"; } 42 Status Process() override; GetPreservedAnalyses()43 IRContext::Analysis GetPreservedAnalyses() override { 44 return IRContext::kAnalysisDefUse | 45 IRContext::kAnalysisInstrToBlockMapping | 46 IRContext::kAnalysisDecorations | IRContext::kAnalysisCombinators | 47 IRContext::kAnalysisCFG | IRContext::kAnalysisDominatorAnalysis | 48 IRContext::kAnalysisNameMap; 49 } 50 51 private: 52 // Return the number of subcomponents in the composite type |typeId|. 53 // Return 0 if not a composite type or number of components is not a 54 // 32-bit constant. 55 uint32_t NumComponents(Instruction* typeInst); 56 57 // Mark all inserts in instruction chain ending at |insertChain| with 58 // indices that intersect with extract indices |extIndices| starting with 59 // index at |extOffset|. Chains are composed solely of Inserts and Phis. 60 // Mark all inserts in chain if |extIndices| is nullptr. 61 void MarkInsertChain(Instruction* insertChain, 62 std::vector<uint32_t>* extIndices, uint32_t extOffset, 63 std::unordered_set<uint32_t>* visited_phis); 64 65 // Perform EliminateDeadInsertsOnePass(|func|) until no modification is 66 // made. Return true if modified. 67 bool EliminateDeadInserts(Function* func); 68 69 // DCE all dead struct, matrix and vector inserts in |func|. An insert is 70 // dead if the value it inserts is never used. Replace any reference to the 71 // insert with its original composite. Return true if modified. Dead inserts 72 // in dependence cycles are not currently eliminated. Dead inserts into 73 // arrays are not currently eliminated. 74 bool EliminateDeadInsertsOnePass(Function* func); 75 76 // Return true if all extensions in this module are allowed by this pass. 77 bool AllExtensionsSupported() const; 78 79 // Live inserts 80 std::unordered_set<uint32_t> liveInserts_; 81 82 // Visited phis as insert chain is traversed; used to avoid infinite loop 83 std::unordered_map<uint32_t, bool> visitedPhis_; 84 }; 85 86 } // namespace opt 87 } // namespace spvtools 88 89 #endif // SOURCE_OPT_DEAD_INSERT_ELIM_PASS_H_ 90